The boat the man was driving crashed into a barge near the Tappan Zee Bridge.

The man, Jojo K. John, was charged with 18 counts. The indictment cited a toxicology report indicating he had a blood alcohol level of 0.15, nearly twice the legal limit. Thomas P. Zugibe, the Rockland County district attorney, said in the indictment that there was also evidence of cocaine in Mr. John’s system.

Mr. John “is accused of taking the helm of his boat while under the influence of alcohol, being unable to maintain situational awareness and striking a construction barge,” the indictment said.

A lawyer for Mr. John, David D. Narain, said the defense disputed the toxicology report, would challenge its findings and had “uncovered substantial evidence, including physical evidence and the testimony of numerous witnesses, that the cause of this tragic accident was the poorly and inadequately lit group of barges struck by Jojo John’s boat.”

The families of those killed, Lindsey Stewart and Mark Lennon, both 30, expressed dismay in July at the “rush, by some, to cast blame on or even malign the victims” as being intoxicated. Phone calls to numbers listed for relatives were not answered on Thursday.